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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2018-02-14 21:25:42 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-02-16 12:48:49 +0300 |
| commit | 6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 (patch) | |
| tree | 974d247b3c7459a2d595cc837d69ab84f57913a5 /Documentation/x86/x86_64 | |
| parent | 91f606a8fa68264224cbc76888fa8649cdbe9990 (diff) | |
| download | linux-6657fca06e3ffab8d0b3f9d8b397f5ee498952d7.tar.xz | |
x86/mm: Allow to boot without LA57 if CONFIG_X86_5LEVEL=y
All pieces of the puzzle are in place and we can now allow to boot with
CONFIG_X86_5LEVEL=y on a machine without LA57 support.
Kernel will detect that LA57 is missing and fold p4d at runtime.
Update the documentation and the Kconfig option description to reflect the
change.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214182542.69302-10-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/x86/x86_64')
| -rw-r--r-- | Documentation/x86/x86_64/5level-paging.txt | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/Documentation/x86/x86_64/5level-paging.txt b/Documentation/x86/x86_64/5level-paging.txt index 087251a0d99c..2432a5ef86d9 100644 --- a/Documentation/x86/x86_64/5level-paging.txt +++ b/Documentation/x86/x86_64/5level-paging.txt @@ -20,12 +20,9 @@ Documentation/x86/x86_64/mm.txt CONFIG_X86_5LEVEL=y enables the feature. -So far, a kernel compiled with the option enabled will be able to boot -only on machines that supports the feature -- see for 'la57' flag in -/proc/cpuinfo. - -The plan is to implement boot-time switching between 4- and 5-level paging -in the future. +Kernel with CONFIG_X86_5LEVEL=y still able to boot on 4-level hardware. +In this case additional page table level -- p4d -- will be folded at +runtime. == User-space and large virtual address space == |